| The multiresidue determination method of three fluoroquinolones in broiler chickentissues after a single oral administration and the depletion of these three fluoroquinolonesafter serial daily oral administration (10mg/Kg.d) for four days were studied in this paper. The ciprofloxacin,norfloxacin,enrofloxacin,which were widely used in animalhusbandry were selected for the research .The residue was extracted with phosphate buffersolution (PBS) and cleaned up by solid-phase extraction column C18and determinnated byhigh perfomance liquid chromatography (HPLC) analysis.The samples were analyzed by afluorescence detector (FLD) at excitation wavelength of 278nm and an emissionwanelength of 465nm; Column temrerture was 40oc; flow rate was 1.0mL/min;injection volumn:20μL. The retention time was: for ciprofloxacin, 5.54 min; for norfloxacin, 5.01 min; forenrofloxacin 7.15 min.The minimal detection limits for the determination (μg/g) were 0.020for ciprofloxacin, 0.025 for norfloxacin, and 0.025 for enrofloxacin. Calibration graphswere prepared for all tissues and good linearity was achieved over the concentration(50-1000ng/mL (g)) ranges tested (r=0.9998 for ciprofloxacin, r=0.9996 for norfloxacin,r=0.9998 for enrofloxacin). The results indicated the method for the multiresiduedeterminstion for three fluoroquinolones in the tissues of broiler chicken was simple,spectific, accurate and aensitive. The average recoveries (%),average coefficients of variation (%) were: forciprofloxacin, 82.1,3.08 in plasma, 75.14,7.20 in muscle, 74.72,12.02 in liver, 74.67,6.35 in kidney; for norfloxacin, 83.14,2.88 in plasma, 80.53,10.29 in muscle, 78.78,13.73 in liver, 78.71,11.19 in kidney; for enrofloxacin, 82.58,4.26 in plasma, 77.22,12.22in muscle, 72.79,11.10 in liver, 790.7,5.89 in kidney. After a single oral administration of ciprofloxacin,norfloxacin,enrofloxacin and theirmixture, these three residues can be detected in plasma, muscle, liver and kidney. Theconcentrations of the residues in each tissue were: the hightest in liver, higher in kidney, thelowest in plasma. After oral administration of ciprofloxacin, the time to reach maximumconcentration in muscle was 14h and 7h in liver and kidney,and the residues in plasma andtissues were still above the MRLs after 48h. After a single oral administration of norfloxacin,the residue concentration was below after 48h. After a single oraladministration ofenrofloxacin., the enrofloxacin and its mestabolite ciprofloxacin residues can be detected inliver and kidney, but in plasma and muscle, ciprofloxacin residues can not be detected. Aftera single oral administration of the mixture, the residue concentration reach the higest in 12hand blow the MRLs after 48h in plasma, but there was a flip-flop in kidney. The depletionrate of 3FQs was quickly in muscle and slowly in liver. After serial daily ora ladministration of ciprofloxacin, norfloxacin, enrofloxacin forfour days, residues of this 3 FQs can be detected in various tissues at the 2nd withdrawaldays, residues of this 3 FQs in plasma was lower than MRLs at the 5th withdrawal day, butthe tissues still had high remains,at the 10th withdrawal day, norfloxacin and enrofloxacinwas not detected in plasma, ciprofloxacin in plasma was lower than MRLs, at 16thwithdrawal day, the residues concentration of nrofloxacin and ciprofloxacin was still abovethe MRLs, at 22th withdrawal day, only ciprofloxacin was detected in liver and at 29thwithdrawal day, no residues can be detected. So, the withdrawal time of norfloxacin wasrecommended as about10d, enrofloxacin and ciprofloxacin were both about 16d.
|
PDF Full Text Request